Hello,

Do you mean

1. This Is The Title

or

2. THIS IS THE TITLE

Firstly, I don't believe Google would penalisise the site, if you decide to use 'THIS IS THE TITLE' but capitalising everything is hard to read, somewhat unprofessional and possibly SPAMMY.  A good article to read would be: http://uxmovement.com/content/all-caps-hard-for-users-to-read/.  Although there is no direct effect, having capitals could decrease the CTR, so if you were ranked in position 3, and your CTR (lower) or bounce rate (higher) than normal, it could be signal your websites content is not up to scratch, thus your rankings could be effected in that regard.

As such I would not recommend your client in using CAPS for the whole meta title as it will penalise the site more than actually helping it.

Hello,

Do you mean

1. This Is The Title

or

2. THIS IS THE TITLE

Firstly, I don't believe Google would penalisise the site, if you decide to use 'THIS IS THE TITLE' but capitalising everything is hard to read, somewhat unprofessional and possibly SPAMMY.  A good article to read would be: http://uxmovement.com/content/all-caps-hard-for-users-to-read/.  Although there is no direct effect, having capitals could decrease the CTR, so if you were ranked in position 3, and your CTR (lower) or bounce rate (higher) than normal, it could be signal your websites content is not up to scratch, thus your rankings could be effected in that regard.

As such I would not recommend your client in using CAPS for the whole meta title as it will penalise the site more than actually helping it.